ok kids, ready for this? a bunch of perl+xml links for you (and me!):

The Source page:

Perl and XML

more Perl and XML

xml and sax machines part one and part two

schematron - Web Content Validation with XML::Schematron

XML and modern CGI applications.

XML::LibXML - An XML::Parser Alternative

Transforming XML With SAX Filters.

Writing SAX drivers for non-XML stuff. interesting.